Remove all racials from Alliance and prevent them from engaging in combat, upon entering a zone or instance you will see a game engine cinematic of your character (and party members!) killing the various mobs and monsters within and walking out will loot (if the built in loot system game you any) This will provide a clear distinction between the two factions, one will be for playing the game, the other will be for RP'ing. Everybody is happy!

I'm curious as to where you're getting your information about the dire situation that is faction balance and/or why you care so much what faction the high end guilds are playing on.